Intermittently driven thread transporting apparatus



June 27, 1967 R. SCHMIDT ET AL 3,327,499

INTERMITTENTLY DRIVEN THREAD TRANSPORTING APPARATUS Filed March 22, 1966 6 Sheets-Sheet l I @IEI F/G.7 Q

June 27, 1967 R. SCHMIDT ET l- INTERMITTENTLY DRIVEN THREAD TRANSPORTING APPARATUS Filed March 22, 1966 6 Sheets-Sheet nbw ALI

June 27, 1967 INTERMITTENTLY Filed March 22, 1966 STATION I STATION III STATION III STATION 11 R. SCHMIDT ET DRIVEN THREAD TRANSPORTING APPARATUS 6 SheetsSheet 5 June 27, 1967 R SCHMIDT ET AL 3,327,499

INTERMITTENTLY DRIVEN THREAD TRANSPORTING APPARATUS Filed March 22, 1966 6 Sheets-Sheet 4 FIG. 4

FIG. 4a

June 27, 1967 R SCHMIDT ET AL 3,327,499

lNTERMITTENTLY DRIVEN THREAD. TRANSPORTING APPARATUS Filed March 22, 1966 6 Sheets-Sheet 5 FIG. 5

1 '1 M HM U 1'; illlll R. SCHMIDT ET AL 3,327,499

INTERMITTENTLY DRIVEN THREAD TRANSPORTING APPARATUS 6 Sheets-Sheet 6 June 27, 1967 Filed. March 22, 1966 A A oE United States Patent 3,327,499 INTERMITTENTLY DRIVEN THREAD TRANSPORTING APPARATUS Richard Schmidt, Stuttgart-Vaihingen, and Hans Joachim Stock, Freiburg im Breisgau, Germany, assignors to Franz Morat GmbH, Stuttgart-Vaihingen, Germany Filed Mar. 22, 1966, Ser. No. 543,455 Claims priority, application Germany, July 6, 1964, M 61,621 19 Claims. (Cl. 66-132) The present application is a continuation-in-part application of our copending application Ser. No. 395,787, filed Sept. 11, 1964, now abandoned.

The present invention relates to an intermittently driven thread transporting apparatus, and more particularly to a circular knitting machine provided at each knitting station with thread transporting means independent- 1 y driven by intermittently moving electric stepping m0- tors.

It is known to provide circular knitting machines with program controlled thread transporting means at the knitting stations which permit variations of the speed at which the thread is delivered to the knitting needles at the knitting stations. For example, the German Auslegeschrift 1,074,810, the German Patent 907,927, and the British Patent 430,744 disclose such apparatus.

. It is also known to transport thread to the knitting stations without any slippage in a positive manner which has the advantage that the loops are of uniform and regular shape which is particularly advantageous for plain and ribbed fabrics.-

The thread, may be wound in several loops about a transporting roller, or be clamped between a pair of transporting rollers to assure a positive transport without slippage. Other thread transporting apparatus includes a pair of meshing gears between which the transported thread is located. Positive thread transporting means of this type are located at each knitting station and are driven by means of belts and pulleys, or other transmissions from the needle cylinder, or from a part moving in synchronism with the needle cylinder.

Thread transporting means which have to transport a thread without slippage cannot be provided with independent electric motors since the speed of the transported thread must be proportionate to the speed of the knitting operation, as represented by the rotary speed of the needle cylinder; Independent drive motors can be used for thread transporting means which operate with slippage ina non-positive manner, but such thread transporting means are suitable only for a patterned fabric in which for different stitches more or less thread is required.

Positive thread transporting means according to the prior art are driven by mechanical transmissions from the needle cylinder of the knitting machine which has the disadvantage that a great amount of space is required for the transmission parts at each knitting station, which is particularly disadvantageous for modern circular knitting machines with many knitting stations.

It has not been considered possible to provide independent electric motors at each knitting station for driving the thread transporting apparatus, since it is absolutely necessary to drive the thread transporting apparatus at a speed proportionate to the speed of the knitting cylinder. Therefore, the constructions disclosed in the German Patent 1,147,705, the a French Patents 916,418 and 870,967, and the US. Patents 2,227,355, 2,160,495 and 2,135,756 which provide electric motors for driving thread transporting apparatus permitting slippage of the thread, are not applicable to thread transporting apparatus which 3,327,499 Patented June 27, 1967 ice must transport the thread positively and without slippage.

It is one object of the present invention to overcome the disadvantages of mechanically driven positive thread transporting apparatus, and to provide an independent electric drive motor at each knitting station for driving a thread transporting means at a speed proportionate to the variable speed of the knitting machine, and more particularly of the needle cylinder.

Another object of the invention is to provide an electric stepping motor at each knitting station for driving thread transporting means and to operate the stepping motor in synchronism with the needle cylinder.

Another object of the invention is to drive the thread transporting means by a stepping motor which performs an angular step whenever receiving an impulse and to provide to the stepping motor impulses at a frequency proportionate to the rotary speed of the needle cylinder.

A related object of the invention is to produce the impulses controlling the stepping motor by sensing the passage of needles, or of corresponding parts of the needle cylinder past a fixed point.

With these objects in view, one embodiment of the invention comprises thread transporting means which may be provided at each knitting station of a circular knitting machine; an electric stepping motor intermittently moving depending on impulses received provided at each knitting station for driving the respective thread transporting means; and impulse producing means controlled by a movable part of the knitting machine, for example by the needle cylinder, to produce impulses at a frequency proportionate to the rotary speed of the needle cylinder. The impulse producing means supply impulses to the electric stepping motor which performs an angular step whenever receiving an impulse, so that the frequency of the steps of the motor corresponds to the rotary speed of the knitting machine. In this manner, the thread transporting means at each knitting station are driven at a speed proportionate to the momentary speed of the needle cylinder, and when the speed of the needle cylinder varies, the speed of the thread transporting means is varied to remain proportionate to the present speed of the needle cylinder.

In one embodiment of the invention, electromagnetic sensing means are provided in the vicinity of the needle cylinder, and respond to the passage of the channels in which the cylinder needles slide to produce impulses whose frequency is directly proportionate to the rotary speed of the knitting cylinder. In another embodiment of the invention, a rotary element is driven from the needle cylinder, and produces light'impulses at a corresponding frequency. The light impulses are then sensed by photoelectric sensing means which produce impulses by which the stepping motor is actuated.

By driving the positively operating slippage-free thread transporting means at a speed directly proportionate to the number of revolutions of the knitting cylinder, the ratio between the number of revolutions of the needle cylinder and the speed of the positively transported thread remains constant, even if the rotary speed of the needle cylinder is varied.

When the type of stitch knitted at the knitting machine is varied, for example, when plain stitches follow a ribbed portion of a fabric knitted without a pattern, the speed of the transported thread must be varied to supply the amount of thread required for the particular stitches. The ratio between the number of revolutions of the needle cylinder and the speed of a transporting means must 'be changed for such different stitches, but nevertheless the speed of the transporting means must vary proportionate with variations of the number of revolutions of the needle 3 cylinder while maintaining the ratio for the respective stitch.

In known positively-transporting program controlled thread transporting apparatus, each thread transporting means must have a mechanical device for varying the thread transporting speed in accordance with the amount of thread required for a particular stitch.

In accordance with the present invention, a variable transmission is provided between the needle cylinder and the sensing means of the impulse producing means. By changing the transmission ratio the frequency controlling the stepping motor, and consequently the transporting speed is changed, as required by a particular stitch while the number of revolutions of the knitting cylinder may remain the same. Nevertheless, irrespective of the transmission ratio selected the speed of the thread transporting means will be directly proportionate to the num'ber of revolutions of the needle cylinder, and the speed of the transported thread will vary and remain proportionate to the number of revolutions of the needle cylinder when the rotary speed of the needle cylinder is varied.

In one embodiment of the invention, the transmission drives a rotary element which produces light impulses sensed by the impulse producing means of the stepping motor, and inanot'her embodiment of the invention, the sensing means of the impulse'producing means can be shifted to sense different numbers of light impulses in accordance with the selected transmission ratio. In the same manner as all control impulses of the stepping motor are produced by sensing means at one point of the circumference of the needle cylinder, the selection of different ratios of the transmission between the needle cylinder and impulse producing means can also be controlled from one point. Such selection of a transmission ratio is advantageously achieved by program controlled means which respond to coded information of a tape to vary the transmission ratio, and correspondingly transporting speed of the thread as required by the nature of the knitted stitches.

In another embodiment of the invention, there is no transmission provided between the needle cylinder and the impulse producing means, and the speed of the transported thread is varied in accordance with the nature of the knitted stitches. For example, the transporting roller of the thread is provided with a plurality of circumferential grooves of different diameter into which the thread can be selectively placed by program controlled means so that the speed of the thread depends not only on the speed of the stepping motor, but also on the diameter of the selected groove, the grooves being selected in accordance with the nature of the stitch and the amount of thread required for the particular stitch. In one embodiment, a lever has a thread guiding means for the thread, and is pivotable between positions located opposite different grooves of the transporting roller to place the thread in a selected groove which is shaped to positively transport the thread without slippage.

Complete control of all thread transporting means at different knitting stations from a single command station is possible, and all or only selected thread transporting means may be operated in accordance with a program represented by a program tape which may have perforations, or light-permeable points permitting a magnetic or photoelectric sensing.

When only a small number of ratios is required of the transmission connecting the needle cylinder with the impulse producing means of the first-mentioned embodiments, a plurality of transmissions each driven by the needle cylinder may be provided for driving rotary elements which produce light impulses which are sensed by the impulse producing means. A selector switch is shifted between positions connecting the photoelectric sensing means which sense the light impulse producing elements driven by the different transmissions.

The'selector switch may be operated by program controlled means.

I The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 is a fragmentary schematic, partly perspective View, illustrating the drive of a stepping motor in accordance with one embodiment of the invention;

FIG. 1a is a diagram illustrating the circuit of the stepping motor;

FIG. 2 is a fragmentary schematic perspective view illustrating a thread transporting apparatus for the embodiment shown in FIG. 1;

FIG. 3 is a fragmentary partly schematic and partly perspective view illustrating another embodiment of the invention;

FIG. 4 is a fragmentary schematic view illustrating a transmission for selecting different frequencies for the control of the stepping motor according to another embodiment of the invention;

FIG. 4a is a fragmentary view illustrating a detail of the embodiment of FIG. 4;

FIG. 5 is a partly schematic and partly perspective fragmentary view illustrating a further embodiment of the invention;

FIG. 6 is a diagram illustrating an electric circuit for amplifying and shaping electric impulses;

FIG. 6a is a fragmentary sectional view illustrating an electromagnetic sensing means; and

FIG. 7 is a schematic sectional view illustrating a program controlled selector means.

Referring now to the drawings, and more particularly to the embodiment illustrated in FIGS. 1 and 2, a stepping motor 1 is provided at each knitting station of the circular knitting machine for driving a roller 8 formed with circumferential grooves of different diameter. A lever 11 is secured to a shaft 12 and turnable between angular positions for placing a thread9 passing through a thread eye 10 in a selected circumferential groove of the transporting roller 8. Assuming that stepping motor 1 operates during a given time period at a uniform speed, thread 9 will be transported at dilferent speeds depending on the diameter of the groove in which it is located, and will move at a greater speed when located in a groove having a greater diameter and at a smaller speed when located in a groove having a smaller diameter. Of course, the speed of the thread will also vary in accordance with variations of the speed of the motor 1.

Motor 1 is a stepping motor, preferably of a type disclosed in US. Patent 2,834,896, as schematically indicated in FIG. 1 and FIG. 1a. The field winding U influences the rotor together with a pair of permanent magnets M so that the rotor turns an angular step whenever an impulse is supplied to a field winding. Every half wave of an alternating current constitutes an impulse causing the rotor to start, and to stop again after an angular step, a torque being produced in each angular position of the rotor. An electric stepping motor of this type is capable of intermittently moving at very high excitation frequencies, and is consequently suited to move the thread passing over transporting roller 8 intermittently at the high speed required for the operations of a circular knitting machine. The well known circular knitting machine to which the invention is applied, is represented by the needle cylinder 4 which is only schematically indicated. Cylinder needles 3 extending parallel to the axis of rotation of the needle cylinder 4 are mounted in axially extending grooves 4a spaced in circumferential direction about the periphery of the needle cylinder and cooperate with dial needles, not shown, to knit the thread 9 supplied at each knitting station by a transporting roller 8 driven by a stepping motor 1. For example, if 12 or 24 knitting stations are provided,

12 or 24 stepping motors 1 driving transporting rollers 8 will be required since a stepping motor 1 is provided at each knitting station for controlling the speed of the thread fed at the respective station. FIG. 3 shows, for example, stepping motors 1 at the first four knitting stations. All stepping motors 1 receive impulses from a single impulse producing means or pulse generator means which includes an electromagnetic means 2 which is stationan'ly mounted in the region of the periphery of needle cylinder 4 to sense the cylinder needles or the ridges between which the cylinder needles are mounted in grooves. When during rotation of the needle cylinder 4, successive ridges 4b or needles in grooves 4a pass electromagnetic means 2, they produce in the same impulses at a frequency depending on the rotary speed of the needle cylinder, and also on the number of needles and grooves on the periphery of the needle cylinder so that the rotary speed of the needle cylinder is sensed. The last mentioned number is, of course, constant for each circular knitting machine so that the frequency of the impulses produced by the electromagnetic sensing means 2 is directly proportionate to the rotary speed and the number of revolutions per minute of the needle cylinder. Since the number of needles and corresponding ridges is immaterial, the frequency of the impulses produced in the electromagnetic sensing means 2 can be reduced by sensing every second, third or fourth needle or ridge instead of each needle and ridge. Sensing means capable of producing such impulses may be provided for this purpose at uniform intervals around the periphery of the needle cylinder.

The impulses produced in the electromagnetic sensing means 2 have a wave shape schematically indicated at 2 and are supplied to a pulse shaping device 5 in which they are amplified and transformed into rectangular half waves as schematically indicated at 2" and then amplified and introduced into a flip-flop switching device 6 which feeds rectangular waves schematically indicated at 2" at a phase lag of 180 to transistor power switches 7a and 7b connected to the field windings of stepping motor 1 which are alternately energized by the staggered peaks of the waves.

As shown in FIG. 6a, the electromagnetic sensing means 2 includes a coil 2a and an iron core 2b located opposite ridges 4b and grooves 4a in the needle cylinder 4. As shown in FIG. 6, coil 2a is connected with a bridge circuit B which receives oscillations schematically indicated at G froma 100 kh. generator G which are modulated due to the changes of the magnetic field of sensing means 2 by the ridges 4b and grooves 4a during rotation of the needle cylinder 4 since the field changes influence the equilibrium of the bridge circuit. The modulated voltage 2 is supplied over a transformer T to an amplifier A, rectifier R and demodulator DM of pulse shaper 5 and assumes the wave shapes R and DM'. The pulses are shaped to the rectangular shape 8' by the Schmitt trigger S and pass through a differentiator D and amplifier AA to assume the shapes D and 2". The output of amplifier AA is connected with the input of the amplifier 6a shown in FIG. 1a. The amplified impulses are supplied to a bistable flip flop device 6, and then over a transformer and transistor power switches 7a, 7b to the field windings U of stepping motor 1, as shown in detail in FIG. 1a which is the circuit diagram of a known unidirectional cyclo pulser manufactured by the Sigma Instruments Inc. of Braintree, Mass, which also manufactures the stepping motor disclosed in the US. Patent 2,834,896.

The rotor of the electric stepping motor 1 will turn one angular step whenever receiving an impulse corresponding to a sensed point of the periphery of needle cylinder 4 so that the number of steps of the stepping motor will be directly proportionate to the rotary speed of the needle cylinder and thereby to the knitting speed of the machine. When the rotary speed of the knitting cylinder varies, the speed of the stepping motor 1 will also be varied. Assuming that thread 9 remains in the same groove of transporting roller '8, it will be positively and intermittently transported at a speed which is in a predetermined ratio to the rotary speed of the needle cylinder and will move faster or slower when the needle cylinder rotates faster or slower.

While the speed of a thread transported by transporting roller 8 is always proportionate to the rotary speed of the needle cylinder, the ratio between the two speeds can be varied by placing thread 9 in different circumferential grooves of transporting roller 8. As explained above, this is accomplished by turning lever arm 11 with needle guide 10. Shaft 12 and lever 11 thereon can be turned to different angular positions by electromagnetic means provided in the box 13 as best seen in FIG. 7. For example, corresponding to each groove of transporting roller 8, a lever arm 12a is secured to shaft 12 within box 13 and connected with the movable armature 12b of a correlated solenoid 1311, the armatures 12b of the several electromagnetic means associated with the different positions of lever 11 having different strokes so that whenever one of the solenoids in box 13 is energized, lever 11 is turned to another position in which eye 10 is located to place thread 9 into a different groove on transporting roller 8. In the embodiment shown in FIG. 2 in which six circumferential grooves are provided in transporting roller 8, corresponding six electromagnetic means will cooperate with six lever arms 12a on shaft 12. The electromagnetic means in box 13 are selectively energized in accordance with the type of stitch which is to be knitted at any moment so that the speeds of the trans-.

ported thread corresponds to the nature of the particular stitch.

A decoding translator 14 receives impulses from a sensing means 16 which senses coded information on a program tape 15. Such coded information may be represented by transverse rows of perforations, or of lightpermeable spots of the program tape. In accordance with the coded information read-out by the sensing means 16, the decoding translator 14 will cause energization of a solenoid 13a in box 13 selected in accordance with the coded program on tape 15 and will cause the placement of thread 9 in a corresponding selected circumferential groove of transporting roller 8. When the sensing means 14 senses different coded recordings, decoding translator 14 produces different control impulses for actuating the electromagnetic means 13a, 12b in box 13 to turn shaft 12 with thread guide lever 11 to different angular posit-ions.

Device 11 to 14 preferably of the type disclosed in the copending application Elsaesser Ser. No. 290,977 but any conventional tape read out device may be used. The number of light permeable spots in each read-out transverse row of the program tape is electronically stored and counted by a counter in decoding translator 14 during the following step of the program tape 15 whereupon a control impulse energizes one of the solenoids 13a associated with the respective counted number. This arrangement is well known and not an object of the invention. v

In the embodiment of FIG. 1, the rotary speed of transporting roller 8 is always in the same ratio to the rotary speed of the needle cylinder, and the speed of transporting roller 8 will vary with the speed of the needle cylinder. At any speed of transporting roller 8, the speed of the transported thread 9 can be in one of six different I ratios in relation to the speed of transporting roller 8,

roller 30 through a thread guide 32 and supplied to the cylinder needles 33 on the needle cylinder 4. The thread may be Wound in one or several turns about transporting roller 30 and is tensioned in such a manner as to assure a positive transport of thread 9 without slippage.

Needle cylinder 4 carries a gear ring 17 with which a pinion 1 8 meshes. A gradually variable friction transmission has one friction cone 20 secured to shaft 19 of pinion 18, and another friction cone 22 secured to a shaft 23 which carries a dis-c 26 having perforations 28 disposed along a circle. A friction roller 21 is mounted on a rod 24 in frictional engagement with friction cones 20 and 22, and rod 24 can be shifted in axial direction by electromagnetic means located in box 25. More particularly, rod 24 has a rack portion, not shown, corresponding to the rack portion 24a in FIG. meshing with a gear, not shown, corresponding to gear 43a in FIG. 5. The gear is turned in the same manner as thread guide 10, 11 in FIG. 2 and the device in box 25 corresponds to the device illustrated in FIG. 7, except that the gear is secured to shaft 12 instead of thread guide 10, 11. When solenoids 13a are selectively energized under the control of a decoding translator 14 and sensing means 16, as described with reference to FIG. 2, the gear on shaft 12 is turned different angles to shift rod 24 whereby the transmission ratio is adjusted by the adjusting means 24. The decoding translator 14 operates as described with reference to FIG. 2 and responds to a program represented by rows of recordings on program tape 15 sensed by sensing means 16. Each different recording sensed by read-out head 16 causes the decoding translator to produce an electric control impulse for energizing the respective electromagnetic means 13a, 12b in box 25. Consequently, in accordance with the particular stitch which is knitted at any time, as represented by the coded information of tape 15, adjusting, rod 24 with friction roller 21 will be shifted to vary the transmission of the transmission means 20, 21, 22 whereby the rotary speed of the perforated disc 26 is varied. While disc 26 will always rotate 'at a speed which is proportionate to the rotary speed of needle cylinder 4, and will increase and reduce its rotary speed when the rotary speed of the needle cylinder 4 is increased or reduced, the ratio between the rotary speed of the needle cylinder and the rotary speed of the perforated disc 26 will depend on the variation of the transmission ratio achieved 'by shifting of friction roller 21, under the control of program selector means 16', 14, 25. While FIG. 3 shows a gradually variable friction transmission, a different type of transmission having stages with different transmission ratios may also be used, and such ratios may correspond to different amounts of thread used for different stitches.

A lamp 27 is mounted on one side of the rotary perforated disc 26 so that light will pass through each perforation 28 into a photoelectric sensing means 29, disposed on the other side of disc 26, opposite lamp 27. The number of the impulses produced in the photoelectric sensing means 29 will be proportionate to the rotary speed of disc 26 which depends on the rotary speed of needle cylinder 4. I

The wave-shaped impulses produced by photoelectric sensing means 29, and schematically represented .at 29', are supplied to a pulse shaper 5, and transformed into rectangular half waves schematically represented at 29". More particularly, the impulses produced by the excited photocell 29 are amplified by an amplifier corresponding to amplifier A in FIG. 6, and then supplied to a Schmitt trigger S, differentiator D, and amplifier AA. The impulses at the output of amplifier AA are supplied to the input of the circuit shown in FIG. let for driving stepping motors 1 and thread transporting devices 30 at the knitting stations of the circular knitting machine. Consequently, the number of angular steps of stepping motor 1 will depend on the number of impulses produced in the photoelectric sensing means 29, and thereby on the rotary 8 speed of the output means 23, of transmission 20, 21, 22 and on the rotary speed of the needle cylinder 4.

It will be understood that the speed at which thread 9 is transported by transporting roller 30 at each knitting station is proportionate to the rotary speed of needle cylinder 4 and will be increased or reduced when the needle cylinder rotates faster or slower. However, the actual speed of the thread can be selected by varying the transmission ratio by shifting the transmission by program controlled means.

While in the embodiment of FIG. 1, the selection of different speeds of the thread is obtained by the grooved transporting roller 8 after the stepping motor 1, the transmission 20, 21, 22 of the embodiment of FIG. 3 is provided intermediate the needle cylinder and the impulse producing means 26 to 29 so that not only the speed of each transporting roller, but also the speed of all stepping motors will depend on the condition of the transmission. Only a single transmission need be provided in the embodiment of FIG. 3 to control a stepping motor 1 and a transporting roller 30 provided at each of the knitting stations of the circular knitting machine as schematically shown for knitting stations I-IV.

The modified embodiments of FIGS. 4 and 4a correspond in the general arrangement to the embodiment described with reference to FIG. 3. The needle cylinder has a gear 17 driving a pinion 18 on shaft 19' shown in FIG. 4. A disc 34 is secured to shaft 19' and rotates with the same at a speed proportionate to the rotary speed of the knitting cylinder. In contrast to the embodiment of FIG. 3, the rotary disc 34 has four concentric circles of perforations 35, 36, 37, 38, which, respectively, pass radially spaced aligned pairs of windows 39' and 39 provided in a pair of plates 39.

Four lamps or other sources oflight, 35a, 35b, 35c and 35d are disposed on one side of perforated disc 34, and photoelectric sensing means 351-354 are located on the other side of the perforated disc 34, each lamp being aligned with a pair of windows 39', 39" and with a photoelectric sensing means.

A different number of perforations is provided in each circular row of perforations 35 to 38, and consequently, different numbers of impulses will be generated by the photoelectric sensing means 351 to 358, while the needle cylinder and disc 34 rotate at the same speed. Photoelectric sensing means 351 to 354 are respectively connected to four contacts 40a, 40b, 40c and 40d over which a turnable contact arm 41 passes. Contact arm 41 is operated by electromagnetic means provided in a box 25', and operated by a decoding translator 14 responding to sensing means 16 sensing coded information on a program tape 15. The movable contact arm 41 is turned as'described with reference to FIG. 7 for thread guide 10, 11. Arm 41 is secured to shaft'12, and will be placed in different angular positions depending on which solenoid 13a is selectively energized by program controlled means 14, 15, 16 as explained with reference to FIG. 2..

In accordance with the position of contact arm 41, wave-shaped impulses of different frequencies, as represented at 29' will be supplied to the pulse shaper 5 and transformed into rectangular half waves as schematically represented at 29". As described with reference to FIGS. 1 and 3, the impulses are supplied through a flip flop switching device 6 and transistor switches 7a, 7b to stepping motors 1 which drive transporting rollers 30, as shown in FIG. 3. Components A, S, D, AA of the circuit of FIG. 6 are used as pulse shaper 5, and the rectangular pulses are supplied to the input of the circuit shown in FIG. 6 which includes components 6, 7a, 7b and the stepping motor 1. Assuming that the needle cylinder rotates at a constant speed, the frequency of the impulses supplied to the stepping motor 1 will depend on the position of contact arm 41 of the selector switch since each row of perforations will produce a different number of impulses per time unit while the perforated disc rotates at the same speed. Irrespective of the position of the selector switch, the number of impulses will also be proportionate to the rotary speed of the needle cylinder, and will be higher when the needle cylinder rotates faster, and lower when the needle cylinder rotates slower.

Consequently, the lamps 35a to 35d, rows of perforations 35 to 38, the photoelectric sensing means 351 to 354, and the selector switch 40a to 40d and 41, constitute transmission means for varying the frequency of the impulses received by the stepping motors 1 at the several knitting stations.

As explained with reference to the other embodiments of the invention, the program controlled means 14, control selector means 25' and the selector switch 41 vary the effective transmission ratio in accordance with the nature of the stitch which is to be knitted so that for each stitch a corresponding amount of thread is supplied by the respective stepping motor and transporting roller.

The embodiment of FIG. 5 includes a knitting cylinder 4 provided with a gear 17, as described with reference to FIGS. 3 and 4. A plurality of pinions, for example, three pinions 18a, 18b, 18c mesh with gear 17, and respectively drive friction cones 20a, 20b, 20c of three friction transmissions, which further include friction rollers 21a, 21b, 21c and output friction cones 22a, 22b, 220 which are respectively connected to shafts 23a, 23b, 23c each of which carries a disc 26a, 26b, 26c, respectively.

The friction rollers 21a, 21b, 210 are mounted on rods 24a, 24b, 24c, which have rack portions meshing with pinions 43a, 43b, 43c, which are manually operable by adjusting knobs 42a, 42b, 42c. By operation of the knobs, each friction roller 21a, can be shifted to vary the transmission ratio of the respective transmission so that discs 26a, 26b, 26c rotate at different speeds while needle cylinder 4 rotates at the same speed, and will increase or reduce their speeds when the speed of needle cylinder 4 is increased or reduced. The position of friction rollers 21a, 21b, 21c is only once adjusted for each knitting operation or for several knitting operations, so that the ratio of each of the friction transmissions remains the same during the knitting of a fabric. A source of light 27a, 27b, 270 is provided on one side of each perforated disc 26a, 26b, 260 in' the region of a circular row of perforations 28 of each disc, so that light falls through each of the perforations into the photoelectric sensing means 29a, 29b, 290 which are disposed on the other side of each perforated disc.

The photoelectric sensing means are respectively connected to three contacts 44a, 44b, 44c of a selector switch including a contact arm 45 which is connected to a pulse shaper 5 including components A, S, D, AA of the circuit shown in FIG. 6. Other contacts of the selector switch may be connected to other photoelectric sensing means cooperating with perforated discs driven by other transmissions if a greater number of different frequencies is desired. Contact arm 45 is operated by selector means 25' including electromagnetic means, and operated by decoding translator 14 whose sensing means 16 sense coded information recorded on a program tape 15. A selector means as shown in FIG. 7 is used whose shaft 12 carries contact arm 45 and turns the same angles de termined by the program controlled energization of solenoids 13a. The half waves represented at 29 are supplied through circuits as shown in FIG. 1a to the several stepping motors 1 at the several knitting stations, as described with reference to FIG. .3. Each stepping motor 1 drives a transporting roller 30. These elements are not illustrated in FIG. 5 for the sake of simplicity.

The rotary speed of each perforated disc can be selected by selecting a suitable transmission ratio by operation of the knobs 42, 42b, 420, etc. of the adjusting means of the respective transmission. Since the same number of perforations 28 is provided on each perforated disc, a different number of impulses will be produced in each of the photoelectric sensing means due to different speeds of the perforated discs. Consequently, the speed of the stepping motor and of transporting roller 30 will be different depending on which of the photoelectric sensing means 29a, 29b, 29c is selected in accordance with the program recorded on program tape 15 by shifting contact arm 45 of the selector switch.

If needle cylinder 4 rotates at the same speed, such selection will result in different speeds of the threads according to the nature of the stitches to be knitted as represented by the program tape 15. Irrespective of which transmission is selected and effective, the frequency of the impulses supplied to the stepping motors 1 will depend on the rotary speed of the needle cylinder, and each stepping motor 1 will move faster when needle cylinder 4 rotates faster, and slower when the needle cylinder rotates slower. Consequently, the speed of the thread supplied by the thread transporting roller 30 at several knitting stations, will always be proportionate to the speed of the knitting operations and more particularly to the rotary speed of the needle cylinder.

Embodiments of the invention have been described which are used in combination with a circular knitting machine. The thread transporting apparatus of the invention may be adapted to supply the thread of a flat bed knitting machine, as will be apparent to those skilled in the art.

. It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of thread transporting apparatus, differing from the types described above.

- While the invention has been illustrated and described as embodied in thread transporting means at the knitting stations of a circular knitting machine driven by intermittently operating stepping motors controlled by impulses whose frequency depends on the rotary speed of the needle cylinder, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing'will so fully reveal the gist of the present invention that-others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A knitting machine comprising, in combination, a movable part for performing knitting operations, a plurality of knitting stations, and a thread transporting apparatus ateach knitting station, said thread transporting apparatus comprising impulse producing means controlled by said movable part of said knitting machine to generate electric impulses at a frequency proportionate to the operational speed of the knitting machine; an electric stepping motor connected to said impulse producing means for receiving said impulses and driven by the same to intermittently move in steps whose frequency is proportionate to the frequency of said impulses and thereby to the speed of said movable part and to the operational speed of the knitting machine; and thread transporting means connected to and driven by said stepping motor whereby said thread transporting means move at a speed varying proportionate to any varied speed of the knitting machine.

2. A circular knitting machine according to claim 1 wherein said movable part is a needle cylinder.

3. A knitting machine according to claim 1 wherein said movable part rotates and has a plurality of portions spaced along a circle; and wherein said impulse producing means include sensing means for sensing said spaced portions.

4. A knitting machine according to claim 1 wherein said movable part is a needle cylinder; and including a plurality of portions spaced along a circle and rotating in synchronism with said needle cylinder about the center of said circle; and wherein said impulse producing means include sensing means for sensing said spaced portions so as to produce impulses at a frequency proportionate to the rotary speed of said needle cylinder.

5. A knitting machine according to claim 1 and including selector means having a plurality of positions for causing movement of a transported thread at different speeds while said stepping motor moves at the same speed; and program controlled means for operating said selector means in accordance with a program.

6. A knitting machine according to claim 1 wherein said movable part is a rotary needle cylinder having a plurality of portions spaced along the circumference thereof; and wherein said impulse producing means include sensing means stationarily mounted at a point of the periphery of said needle cylinder for sensing said spaced portions so as to produce impulses at a frequency proportionate to the rotary speed of said needle cylinder.

7. A knitting machine according to claim 1 wherein said movable part is a rotary needle cylinder; and wherein said impulse producing means include a rotary element having a plurality of light-permeable portions spaced along a circle and being driven from said needle cylinder to rotate about the centerof said circle at a speed proportionate to the rotary speed of said needle cylinder, and asource of light in the region of said light-permeable portions, and sensing means for sensing light impulses passing through said light-permeable portions so as to produce impulses at a frequency proportionate to the rotary speed of said needle cylinder.

8. A knitting machine according to claim 1 wherein said thread transporting means includes a roller driven by said stepping motor and having a plurality of circumferential grooves of different diameter adaptedto transport a thread without slippage; and comprising selector means including a movable thread guide having a plurality of positions respectively aligned with said circumferential grooves for placing the thread in the same for causing movement of the thread at different speeds while said stepping motor moves at the same speed; and program controlled means for operating said selector means.-

9. A'knitting machine according to claim 8 wherein said -selector means includes a shaft supporting said thread guide for turning movement between said positions, a plurality of electromagnetic means connected with said shaft for turning the same, respectively, different angles with said thread guide; and wherein said program controlled means include a read-out head for reading out coded recordings on a program tape, and means for producing control impulses for energizing selected electromagnetic means in accordance with the recordings on the tape. v

10. A knitting machine according to claim 1 comprising a needle cylinder; a variable transmission driven from said needle cylinder; a rotary element having a plurality of portions spaced along acircle and being driven from said needle cylinder through said transmission to rotate about the center of said circle; and wherein said impulse producing means include sensing means for sensing said portions so as to produce electric impulses at a frequency determined by the rotary speed of said needle cylinder and by the ratio of a transmission.

11. A knitting machine according to claim 10 wherein said variable transmission includes adjusting means for varying the transmission ratio; and wherein said knitting machine comprises selector means connected to said adjusting means for operating the same so that the thread istransported at different speeds depending on the adjusted transmission ratio while said needle cylinder moves at the same speed; and program controlled means for operating said selector means.

12. A knitting machine according to claim 1 wherein said movable part is a rotary needle cylinder; and wherein said impulse producing means include a rotary element driven from said needle cylinder to rotate about an axis, said rotary element having a plurality of concentric cir-' cular rows of light-permeable portions, a source of light arranged in the regions of said circular rows, a plurality of photoelectric sensing means for respectively sensing light impulses passing through said light permeable portions of said rows; and comprising a selector switch having contacts respectively connected to said photoelectric sensing means and a movable contact arm; selector means for moving said contact arm; program controlled means for operating said selector means; and circuit means connecting said selector switch with said stepping motor to supply to the same impulses produced in a selected photoelectric sensing means so that said motor intermittently moves under control of said impulses.

' 13. A knitting machine according to claim 12 wherein said circuit means include an amplifier and a pulse shaper.

14.'A knitting machine according to claim 1 comprising a plurality of variable transmissions, each transmission including an adjusting means for adjusting the transmission ratio and a drive member driven from said movable part; andwherein said impulse producing means include a plurality of rotary elements respectively driven by said transmissions, each element having a plurality of portions spaced along a circle, and sensing means for respectively sensing portions of said elements; and comprising a selector switch having contacts connected to said sensing means, respectively, and a movable contact arm connected to said stepping motor sothat in accordancewith the positions of the selector switch, diiferent numbers of impulses are conducted to, and actuate said stepping motor depending on the adjusted ratio of the selected transmission so that the rotary speed of said step ping motor is proportionate to the operational speed of the knitting machine and also depends on the ratio of the" selected transmission.

15. A knitting machine according to claim 14 wherein said portions of said rotary elements are light-permeable; and wherein said impulse producing means includes a plurality of light sources respectively located in the regions of said light permeable portions of said rotary elements; and wherein saidsensing means are photoelectric cells responding to light impulses to produce electric impulses supplied to said stepping motor; and comprising program controlled selector means for operating said contact arm of said selector switch.

16. A knitting machine according to claim '14 wherein said transmissions are gradually variable friction transmissions, and wherein said adjusting means is manually sett-able for setting a selected transmission ratio for each transmission.

17. A knitting machine according to claim 1' including an electric circuit connecting said impulse producing means with said electric stepping motor, said electric circuit including amplifier means, a pulse shaping device having a Schmitt trigger, a bistable flip flop device, and transistor power switches.

18'. A knitting machine according to claim 1 and including adjustable means for varying the speed at which the thread is transported by said thread transporting means; and program control-led means for operating said adjustable means so that the speed of the thread is adjusted depending on a program but remains proportionate to the operational speed of said knitting machine.

19. A knitting machine according to claim 18 wherein said adjustable means includes transmission means, and a program controlled adjusting means for varying the ratio of said transmission means; wherein said impulse producing means include a rotary member; and wherein said transmission means connects said movable part of the knitting machine with said rotary member of said impulse producing means.

References Cited UNITED STATES PATENTS Rosenberg BIS-20.110 X Fredrickson 31049 Foulger 310-49 X Mischon 66132 Levine et a1. 66-154 FOREIGN PATENTS Great Britain. Great Britain. Great Britain.

10 MERVIN STEIN, Primary Examiner.

W. C. REYNOLDS, Assistant Examiner. 

1. A KNITTING MACHINE COMPRISING, IN COMBINATION, A MOVABLE PART FOR PERFORMING KNITTING OPERATIONS, A PLURALITY OF KNITTING STATIONS, AND A THREAD TRANSPORTING APPARATUS AT EACH KNITTING STATION, SAID THREAD TRANSPORTING APPARATUS COMPRISING IMPULSE PRODUCING MEANS CONTROLLED BY SAID MOVABLE PART OF SAID KNITTING MACHINE TO GENERATE ELECTRIC IMPULSES AT A FREQUENCY PROPORTIONATE TO THE OPERATIONAL SPEED OF THE KNITTING MACHINE; AN ELECTRIC STEPPING MOTOR CONNECTED TO SAID IMPULSE PRODUCING MEANS FOR RECEIVING SAID IMPULSES AND DRIVEN BY THE SAME TO INTERMITTENTLY MOVE IN STEPS WHOSE FREQUENCY IS PROPORTIONATE TO THE FREQUENCY OF SAID IMPULSES AND THEREBY TO THE SPEED OF SAID MOVABLE PART AND TO THE OPERATIONAL SPEED OF THE KNITTING MACHINE; AND THREAD TRANSPORTING MEANS CONNECTED TO AND DRIVEN BY SAID STEPPING MOTOR WHEREBY SAID THREAD TRANSPORTING MEANS MOVE AT A SPEED VARYING PROPORTIONATE TO ANY VARIED SPEED OF THE KNITTING MACHINE. 